I am using Workdrive TrueSync on my windows pc to open files directly from my windows without having to open them from the workdrive web. 

But, I found something strange, I also have the zoho writer app installed on my windows and if I create a document directly from the writer app, it creates a file with the extension .zdoc which does not sync automatically with workdrive and acts like a local file instead, I have to click on save everytime to actually save it. 

And on the workdrive web, if I click on the .zdoc extension file, it says that to open that file in an editable format zoho needs to change the file format and it changes to an extension showing .zwriterlink.

So isn't zdoc a proprietary extension of zoho and what is the difference between the extension .zdoc and .zwriterlink?